Imperfect Images
No telescope can form a perfect image. Even if a reflecting telescope could have a perfect mirror, or a refracting telescope could have a perfect lens, the effects of aperture diffraction are unavoidable. In reality, perfect mirrors and perfect lenses do not exist, so image aberrations in addition to aperture diffraction must be taken into account. Image aberrations can be broken down into two main classes, monochromatic, and polychromatic. In 1857, Philipp Ludwig von Seidel (1821–1896) decomposed the first order monochromatic aberrations into five constituent aberrations. They are now commonly referred to as the five Seidel Aberrations.
Read more about this topic: Optical Telescope
Famous quotes containing the words imperfect and/or images:
“We can glut ourselves with how-to-raise children information . . . strive to become more mature and aware but none of this will spare us from the . . . inevitability that some of the time we are going to fail our children. Because there is a big gap between knowing and doing. Because mature, aware people are imperfect too. Or because some current event in our life may so absorb or depress us that when our children need us we cannot come through.”
—Judith Viorst (20th century)
“The world is for thousands a freak show; the images flicker past and vanish; the impressions remain flat and unconnected in the soul. Thus they are easily led by the opinions of others, are content to let their impressions be shuffled and rearranged and evaluated differently.”
—Johann Wolfgang Von Goethe (1749–1832)